Fiber waste collector/remover and cooling apparatus for use with a circular knitting machine

Abstract: Fiber waste generated during operation of a circular knitting machine is removed from components of the machine by an air suction/blowing fan motor which causes air currents that conduct the fiber waste to one or more filters. Air suction removes the fiber waste from the filters. An adjustable suction cylinder (21) cooperates with the air suction/blowing fan motor to draw air from below the knitting cylinder (4) through a cooling orifice (26) to simultaneously cool the knitting unit.

Description: The present invention relates to knitting machines, and, more particularly, to an apparatus for collecting and removing fiber waste from a circular knitting machine while cooling the knitting unit thereof. Conventional knitting units of circular knitting machines are traditionally associated with more than 100 yarn supply bobbins. When certain yarns are employed for forming the knitted fabric, dust, lint and waste fibers (collectively referred to hereinafter as "fiber waste") are generated by engagement of the yarns with the machine's yarn feeding, guiding and/or other components of the knitting machine and creel. The amount of fiber waste set adrift in the ambient air is substantial. This amount of fiber waste tends to increase as the operating speed of the knitting machine increases. Once the fiber waste has become airborne, it tends to settle upon the yarn feeders, yarn guides and the knitting unit of the knitting machine, and even upon adjoining machines. This fiber waste occasionally gets knitted into the fabric causing defects in the fabric and in some cases, damage to the needles and other components of the knitting unit. This accumulation of fiber waste necessitates frequent overhauls of the knitting units on the machine which is both costly and time consuming. Various kinds of devices have heretofore been proposed for removing fiber waste generated by the knitting unit. The majority of the prior devices employ either a motor driven fan or an air blower to blow the fiber waste away. It has also been proposed to provide a cover about each knitting machine, and to install an exhaust duct near the machine so that the machine operator may gather the fiber waste and introduce it into an exhaust duct. The large installation costs associated with such a method make it less desirable. In addition, this method requires shielding the machine body which negatively affects access to the machine and the surrounding work environment. Moreover, once lubricants, such as oil, etc., stick on the shielding member, fibers tend to adhere to the shielding member which is both unsightly and unsanitary. As disclosed in U.S. Patent No. 5,177,985, the assignee of the present invention has previously developed a system for the collection and removal of fiber waste which utilizes a fixed suction cylinder which cooperates with the suction/blowing means to direct fiber waste laden air from the knitting unit into a filter means. While this system constitutes a marked improvement in fiber waste removal and collection from circular knitting machines, the system does have limitations due to the fixed character of the suction cylinder. As the operational speed of the knitting machines increases, the elements of the knitting unit begin to overheat, causing heat expansion which results in distortion of the cylinder and its surrounding components. This distortion in turn causes degradation in the accuracy of the knitting machine. However, such distorting and degradation could be prevented if the knitting machine was cooled during operation. Heretofore, no effective cooling of the knitting unit during operation has been made available. In view of the foregoing background, it is an object of the present invention to provide apparatus in a circular knitting machine which collects and removes fiber waste while also cooling the knitting unit thereof. The invention consists in a circular knitting machine including a knitting unit having a rotating needle cylinder and knitting elements carried by the needle cylinder for knitting fabric from yarns supplied thereto, and apparatus for removing and collecting the fiber waste comprising a filter for collecting fiber waste, and air suction/blowing means for producing an air flow through the knitting unit to remove fiber waste therefrom and carry the fiber waste to the filter, characterised by positioning means for positioning the knit fabric relative to the needle cylinder and defining a cooling orifice therebetween, and an adjustable suction cylinder located between the needle cylinder and the air suction/blowing means for producing therewith suction for drawing fiber waste laden air through said suction cylinder into said filter and for drawing air through said cooling orifice for cooling the knitting unit. The suction cylinder may be adjustable relative to the air suction blowing means and the knitting unit so that the amount of air flow through the knitting unit may be increased or decreased. Hence, with the invention, a cooling orifice is created between the inside of the needle cylinder of the knitting machine and the knit fabric being produced to cool the knitting unit while fiber waste is removed therefrom. This orifice may be formed by an orifice disk which controls and positions the knit fabric inside the needle cylinder in such a manner that the air currents are directed or channelled to and across the knitting unit. It is preferable that the cooling orifice be a channel having a cross section which decreases as it approaches the knitting unit and which causes air to speed up as it passes therethrough to cool the knitting unit. Increasing the air speed passing through the cooling orifice improves the cooling effect of the air. In order that the present invention may be more readily understood, reference will now be made to the accompanying drawings, in which:- Fig. 1 is a front elevational view of a circular knitting machine having a fiber waste collector, remover and cooling apparatus in accordance with a first embodiment of the invention, Fig. 2 is an enlarged sectional view of a portion of the knitting unit shown in Fig. 1, Fig. 3 is an enlarged part sectional view of the fiber waste collection and remover of Fig. 1, Fig. 4 is an enlarged view of the knitting unit and the cooling device of Fig. 1, Fig. 5 is a front elevational view of an alternative embodiment of the present invention, Fig. 6 is a front elevational view of another alternative embodiment of the present invention, and Fig. 7 is a top plan view of the embodiment shown in Fig. 6. A circular knitting machine 99 as shown in Figs. 1 through 4, has a plurality of legs 1 supporting a bed or frame 2 that in turn supports a circular knitting unit 3 . The knitting unit 3 as shown in Figs. 1 and 2, includes a needle cylinder 4 rotatably supported on the frame 2 , yarn feeders 5 and sinkers 6 . Located above the knitting unit 3 , is a fiber waste collector/remover 7 for collecting and removing fiber waste generated during operation of circular knitting machine 99 . As shown best in Fig. 3, the fiber waste collector/remover 7 includes an annular filter 8 , a suction/blowing means 9 , preferably a motor driven fan 9 and a filter cleaner 10 . Rotative movement is imparted to either the filter cleaner 10 or the filter 8 , so that they may rotate relative to each other, by a drive motor 11 . The filter 8 may be divided into two or more vertical sections, which are joined together in a conventional manner to create an integral unit. The filter 8 includes a first surface 8a and an opposite second surface 8b such that fiber waste may be collected on either surface 8a or 8b . In the embodiments shown, waste fibers are collected on first surface 8a . The filter 8 has a large number of perforations which are preferably between 8-16 meshes per cm (20-40 meshes per inch). The preferred mesh number is 12 meshes per cm (30 meshes per inch) which allows fiber waste collected on either surface to be withdrawn by the filter cleaner 10 operating along the first surface 8a . Wire nets or similar filter substitutes with comparable perforations may be employed in accordance with this invention. In the embodiment shown in Fig. 3, the filter 8 is fixed along its bottom portion to a circular bottom plate 13 which projects radially outward toward the upper portion of a yarn carrier 12 (shown in Fig. 1). The bottom plate 13 has a cup-shaped area which forms a center region 14 . The center region 14 provides sufficient room for the air suction/blowing means 9 , which in this embodiment is a motor fan, to be supported and centrally located above the knitting unit 3 . The bottom plate 13 , the filter 8 and the filter cleaner 10 are positioned above the knitting unit 3 by vertical extending posts 30 positioned on the frame 2 (as shown in Fig. 1). Still referring to Fig. 3, the filter cleaner 10 includes a tip opening 10a which has a flared head sized to correspond to the width of the first surface 8a of the filter 8 so that one rotation of either the filter cleaner 10 or the filter 8 relative to each other cleans the entire filter. The tip opening 10a is attached at one end to a first horizontal portion 10b extending horizontally toward the center region 14 . A vertical portion 10c extends vertically upward from the fan motor 9 generally transverse to the first horizontal portion 10b . An elbow portion 10e joins the first horizontal portion 10b and the vertical portion 10c . A T-shaped portion 10f extends vertically upward from vertical portion 10e such that second horizontal portion 10d is attached thereto and is located in parallel alignment above first horizontal portion 10b . In this embodiment, portions 10a , 10b , 10c , and 10e form an integral unit which is rotatably driven by driving means 11 , enabling the filter cleaner to rotate around vertical portion 10c to clean along the first surface 8a of the filter 8 . It is to be understood that in an alternative embodiment shown in Fig. 5, (described below in greater detail), the filter cleaner 10' remains stationary while the drive means 11' rotates the filter 8' relative thereto. The drive means 11 includes a first spur gear 17 mounted on a shaft end of a gear motor 16 . A second spur gear 18 is mounted on the periphery of the vertical portion 10c of the cleaning filter 10 . A motor stand 19 surrounds the spur gears 17 and 18 and provides support for a center member 20 on which the gear motor 16 is mounted. This arrangement of the gear motor 16 allows the gear motor 16 to revolve at a slow speed, with the interval of operation predetermined by a timer (not shown). When activated, the gear motor 16 revolves the filter cleaner 10 around the inside of the filter 8 along the first surface 8a thereof to remove fiber waste collected on the first surface 8a of the filter 8 . An adjustable suction cylinder 21 is located below the motor fan 9 . The suction cylinder 21 , of the embodiment shown in Figs. 1 and 4, is constructed of transparent plastic material that is vertically divided into several sections or pieces. The pieces are concentrically arranged to allow slidable vertical adjustment relative to one another. The suction cylinder 21 is located between the motor fan 9 and the knitting unit 3 . The suction cylinder 21 has an external diameter at least equal to the external diameter of the knitting unit. In this embodiment, the suction cylinder 21 is supported in position by a center shaft 22 extending vertically between the fan motor 9 and the frame 2 . Radial supports 23 attached to the center shaft 22 and extending radially horizontally outward therefrom assist in supporting the suction cylinder 21 (see Fig. 4). Between the upper portion of the suction cylinder 21 and the motor fan 9 is an upper gap 24 (shown in Fig. 1). A lower gap 25 is located between the lower portion of the suction cylinder 21 and the needle cylinder 4 . To ensure that an optimum vacuum is formed by the suction cylinder 21 , while still allowing ambient air to flow into the suction cylinder 21 , it is important to position the suction cylinder 21 as close to the needle cylinder 4 as possible, making the lower gap 25 as small as possible. The ability to vertically adjust the suction cylinder 21 by vertical movement of the concentrically arranged divided sections of the suction cylinder 21 , relative to one another, allows for the adjustment of the size of the upper gap 24 and the lower gap 25 which in turn adjusts the amount of air intake in each of the gaps 24 and 25 . This ability to vertically adjust the suction cylinder 21 has a further advantage of enabling easy repair to the knitting unit 3 and its related components without requiring disassembly of the suction cylinder 21 . As best shown in Fig. 4, an orifice disk 27 is mounted on the center shaft 22 in horizontal alignment with the bottom of the base portion 29 of the needle cylinder 4 . The orifice disk 27 has a dual purpose. One purpose is to take the circular knit fabric N , which is cylindrical as it leaves the knitting unit 3 , and spread or stretch it so that the knit fabric N can be wound flat on a take-up roll (not shown) located beneath the knitting unit 3 . To assist in this function, the orifice disk 27 of this embodiment has a circular shape. It is to be understood that other shapes may also be utilized. A second purpose of orifice disk 27 is to define a cooling orifice 26 located between the needle cylinder 4 of the knitting unit 3 and the fabric N . The cooling orifice 26 is a channel that runs the height of the needle cylinder 4 , which has a cylinder portion 28 and a base portion 29 which supports the cylinder portion 28 . The cooling orifice 26 cross section decreases as it approaches the knitting unit which causes the air passing therethrough to speed up to cool the knitting unit 3 . In this embodiment, the preferred cross section of the cooling orifice 26 is between 2-5cm. Increasing the air speed passing through the cooling orifice 26 improves the cooling effect of the air. In operation, the fan motor 9 draws air from beneath the knitting unit 3 in the direction of the arrows which appear on Figs. 1 and 4, as a result of the suction or vacuum created by the suction cylinder 21 . Because of the cross sectional size of the cooling orifice 26 , the air is forced to speed up, which improves its cooling effect, as it travels over the needles (not shown) on the needle cylinder 4 , the sinkers 6 and the other moving parts of the knitting unit 3 . An experiment was conducted to compare how the temperature varied between the machines with and without an orifice and a suction cylinder. The comparison was done by measuring various parts, labeled A through F in Fig. 4 (which correspond to the temperatures appearing in the table below) after running the machines unloaded for 1,200 hours at a room temperature of 26°C. The results of the experiment are summarized in the table below. Location of Temperature Measurement Prior Art (without a cooling orifice or a suction cylinder) Invention (with a cooling orifice and a suction cylinder) Temperature Difference A 73.4 C 65.2 C 8.2 C B 66.7 C 61.9 C 4.8 C C 61.4 C 54.9 C 6.5 C D 65.4 C 59.1 C 6.3 C E 57.2 C 40.4 C 16.8 C F 72.8 C 52.0 C 20.8 C As is evident from the results shown in the table, the inclusion of a cooling orifice and an adjustable suction cylinder in the present invention has significantly reduced the operating temperature of the knitting unit. Continuing with the operation of the invention, the fiber waste which is generated by the knitting process at the knitting unit 3 is driven upward by cooperation between the motor fan 9 and the suction cylinder 21 . The fiber waste is conducted upward into the suction cylinder 21 (as shown by the arrows in Figs. 1 and 4), and then into the filter 8 . The fiber waste is trapped and collected along the first surface 8a of the filter 8 . The filter cleaner 10 is periodically activated by a timer (not shown) which activates the gear motor 16 . The gear motor 16 rotates the integral portion of the filter cleaner 10 (elements 10a , 10b , 10c , and 10e ) so that the tip opening 10a travels along the first surface 8a of the filter 8 to remove the fiber waste which has collected thereon since the previous pass-by of the tip opening 10a . The fiber waste then travels through the remaining portions of the filter cleaner 10 until it reaches a flexible tube 10g . The fiber waste travels through the flexible tube 10g to a suction device 15 where the fiber waste is stored until it is disposed of as desired. Fig. 5 illustrates an alternative embodiment of the present invention. In this embodiment, the invention operates in a manner similar to that described with regard to Figs. 1-4, except that rather than having a filter cleaner 10 rotate relative to a fixed filter 8 , in this embodiment the filter 8' rotates relative to a fixed filter cleaner 10' . As is clearly shown in Fig. 5, the vertical portion 10c' of the filter cleaner 10' extends downward from the first horizontal portion 10b' rather than upward therefrom. In this embodiment the vertical portion 10c' and the first horizontal portion 10b' may be constructed of a single C-shaped piece. This new arrangement of the filter cleaner 10' allows the filter cleaner to remain stationary. The gear motor 16' in this embodiment is attached to the filter 10' in much the same manner as the filter cleaner 10 of the previous embodiment. The gear motor 16' rotates at a slow rate to revolve the filter 8' relative to the fixed filter cleaner 10' so that the first surface 8a' of the filter 8' passes in front of the tip opening 10a' to remove fiber waste from the filter 8' . An additional difference between the first embodiment shown in Figs. 1-4 and the present embodiment illustrated in Fig.5 is the location of the fan motor 9' . In this embodiment, the fan motor 9' is positioned farther from the filter 8' than before. The fan motor 9' is supported by the radial supports 23' attached to vertical extending posts 30' and the fan motor 9' is located closer to the knitting unit 3' of the circular knitting machines 99' . In all other respects, the embodiment shown in Fig. 5 functions in the same manner as previously described. Figs. 6 and 7 illustrate a third embodiment of the present invention. In Figs. 6 and 7, rather than utilizing a flexible tube 10g to remove the fiber waste from the knitting machine 99 , a series of ducts 35 are utilized to remove the fiber waste and transport it to the suction device 15'' . In this embodiment, the ducts 35 are of rigid construction. However, it is to be understood that a more flexible construction may be utilized. The duct 35 has a first vertical portion 10c'' which extends upward from the motor fan 9'' . The first vertical portion 10c'' has a suction opening 36 . The suction opening 36 is supported by a frame 37 . The fan motor 9'' is in turn supported by the suction opening 36 . A first horizontal portion 10b'' extends radially outward from the knitting machine 99" . A first elbow portion 10e" joins the first vertical portion 10c" and the first horizontal portion 10b" . A second vertical portion 10g" extends downward from the first horizontal portion 10b" in generally parallel alignment with the knitting machine 99" . A fiber waste-collection net 38 is located between the second vertical portion 10g" and the suction device 15" . A second elbow portion 10h joins the first horizontal portion 10b" and the second vertical portion 10g" . An exhaust opening 39 is located in the second vertical portion 10g" for allowing some of the air to exhaust to atmosphere. An acceptable alternative to the embodiment shown in Fig. 6 is to locate or mount the motor fan 9" within the first horizontal portion 10b" or on the bottom of exhaust opening 39 . Movement of the motor fan to either of these locations will not affect the function or performance of the motor fan 9" .

Claims: A circular knitting machine (99) including a knitting unit (3) having a rotating needle cylinder (4) and knitting elements carried by the needle cylinder (4) for knitting fabric from yarns supplied thereto, and apparatus for removing and collecting the fiber waste comprising a filter (8) for collecting fiber waste, and air suction/blowing means (9) for producing an air flow through the knitting unit to remove fiber waste therefrom and carry the fiber waste to the filter, characterised by positioning means (27) for positioning the knit fabric (N) relative to the needle cylinder (3) and defining a cooling orifice (26) therebetween, and an adjustable suction cylinder (21) located between the needle cylinder (3) and the air suction/blowing means (9) for producing therewith suction for drawing fiber waste laden air through said suction cylinder (21) into said filter (8) and for drawing air through said cooling orifice (26) for cooling the knitting unit (3). A machine according to claim 1, wherein said positioning means (27) comprises an orifice disk (26) located below the knitting unit (3) for stretching and supporting the knit fabric (N). A machine according to claim 1 or 2, wherein said cooling orifice (26) comprises a channel having a cross section which narrows as it approaches the knitting unit (3), thereby causing air to speed up as it passes therethrough for cooling the knitting unit (3). A machine according to claim 1, 2 or 3, wherein the air suction/blowing means (9) is located above the knitting unit (3), and wherein a center shaft (22) extends vertically at least between said air suction/blowing means and the knitting unit for supporting the suction cylinder (21), and a plurality of radial supports (23) extending radially outward from said center shaft (22) for supporting said suction cylinder (21). A machine according to any preceding claim, wherein said suction cylinder (21) comprises a plurality of divided sections concentrically arranged and wherein at least one of said divided sections is vertically slidable relative to another of said plurality of divided sections for selective vertical adjustment thereof. A machine according to any preceding claim, wherein said suction cylinder (21) is generally centrally located over the knitting unit (3). A machine according to any preceding claim, wherein said suction cylinder (21) has an outer diameter generally equal to an outer diameter of the knitting unit (3). A machine according to any preceding claim, wherein said air suction/blowing means (9) draws air upwards thorough the knitting unit (3) and said cooling orifice (26) to cool the knitting unit (3).

Inventors: IZUMI TOSHIRO, KAWASE SHINJI, IZUMI, TOSHIRO, KAWASE, SHINJI
Applicants: PRECISION FUKUHARA WORKS LTD, PRECISION FUKUHARA WORKS, LTD
Application year: 1994
Main classification: D04B35
IPC codes: D04B35, D04B15